Pretend it's alive

August 09, 2010

Hours after Friday's swimming tragedy in Lake Michigan, Coast Guard Petty Officer Brandon Blackwell paid due respect to Chicago's inland ocean: "People have the misconception that the lake is like a giant swimming pool," he told the Tribune's Cynthia Dizikes. "But it is affected by undertows and currents and is a lot more dangerous than people realize."

We offer no comment beyond profound sympathy to the families of the two young men lost in that early-morning incident, and to the two young women who survived. We're not here to scold or to criticize.

We're here with a reminder that while Lake Michigan isn't sentient, it behaves as if it has a mind of its own. Maybe several minds:

The undertow more muscular than its ripples on the surface, the rip current that thrusts speedily away from shore, the slithery fog that robs boaters of visual clues — the lake camouflages its mysteries. Yet risk is part of its allure. If we only wanted fresh air and cool water, we'd open a window and sit in the tub. Lake Michigan means expanse and personal freedom. As a sign we once saw near an Irish lake put it, "Wild Swimming Allowed."

Safety instructors offer advice that, if so many among us didn't flout it, would seem self-evident: Don't mix water with alcohol, wear a life jacket if you're not in a designated (and lifeguarded) swim area, watch those around you to see if anyone's arms appear to be climbing a nonexistent ladder, or if his head bobs low to the water — either can be a sign that your companion is helpless. Don't await his call for help; for a variety of reasons, he may not have enough breath. We're also partial, in boats, to the notion of a designated sailor, one person who will not drink because … you just never know.

The fact that, on Friday, the young women survived circumstances that their male companions did not isn't a surprise. The threat to both genders is daunting: Water extracts body heat some 20 times faster than does air of the same temperature. Among adults, the average woman — because her body is smaller — typically cools quicker than does the average man. But if she avoids fully submerging below the water, or generates heat by treading water, she has less mass to warm than he does. As minutes or hours pass, her body core cools more slowly than his.

Children of either gender face their own special risk: Kids' bodies, with their high ratios of skin surface to body mass, can lose heat especially quickly.

In these moments of emergency, the human body has tactics for conserving heat — constriction of blood vessels, shivering to generate warmth, insulation of core temperature.

But none of these mere human responses can, for very long, withstand the infinitely greater powers of a body like Lake Michigan.

Which delivers us to the best advice about the lake that we've ever encountered: Pretend it's alive. Yes, alive, with unpredictable moves sure to buffet you and mood swings that test your reactions.

Respect the lake. As the chief petty officer says, it's not a giant pool. And, to echo the good wish you'd hear at that lake in Ireland, "Safe home."